bolt2002Model: Fit graded response model to MP model based on procedure by...

In falkcarl/mpirt: Semi- and non-parametric item response theory

Fit graded response model to MP model based on procedure by Bolt (2002)

Description

Fit graded response model to MP model based on procedure by Bolt (2002)

Usage

bolt2002Model(
  x,
  items,
  theta = seq(-4, 4, length.out = 500),
  w = dnorm(theta)/sum(dnorm(theta))
)

Arguments

x	Fitted mxModel, e.g., from simAnneal.
items	Vector of indices indicating which items to perform procedure for.
theta	Grid across theta over which to perform estimation for Bolt (2002)'s approach.
w	Weights corresponding to theta for performing estimation for Bolt (2002)'s approach.

Details

This function goes item by item for the model in x and uses the procedure by Bolt (2002) to fit a graded response model as best it can to each item's (semi-parametric) response functions.

Value

A list with the following elements

Slots

conv

Convergence code for each item returned from nlminb.

gr.items

A list of item specifications from the graded model.

pars

A list of item parameters from the fitted graded model for each item.

mp.items

A list of item specifications from the MP model.

mp.pars

A list of item parameters from the MP model for each item.

falkcarl/mpirt documentation built on July 11, 2024, 12:09 a.m.